Autolysis of Calcium-Activated Neutral Protease of Chicken Skeletal Muscle1

Abstract

The conditions and process of autolysis of calcium-activated neutral protease (CANP) were examined. Optimal conditions for autolysis were the same as those required for expression of activity of CANP. The autolysis proceeded rapidly by a strictly limited proteolysis. During autolysis the molecular weight of CANP changed from 82 K (native CANP or mCANP) to 79 K and then 60 K. The 79 K and 60 K molecular species were both active at μM order of Ca²⁺(μCANP), whereas the native CANP is active at mM order of Ca²⁺(μCANP). Various proteases examined did not produce μCANP from mCANP under the conditions tested. Furthermore, μCANP did not yield μCANP from mCANP at lower Ca²⁺concen trations where only μCANP was active. Therefore, μCANP is produced from mCANP only by the specific autolysis of mCANP.